The present invention relates a vibration control system for a structure such as a space structure, and an actuator which can be used in such a vibration control system.
A document 1 (Dai 31 Kai Uchukagakugijutsukoenkaikoenshu (1987) pages 400 and 401) shows a conventional vibration control system which employs a cantilever as a simulation model of a space structure. The vibration control system of this example has at least one piezoelectric element attached to one side of the cantilever so that the piezoelectric element elongates in the longitudinal direction, and a controller for damping vibrations of the cantilever by controlling a voltage applied on the piezoelectric element so as to control a longitudinal displacement of the cantilever.
However, this control system is not effective against vibrations of large amplitudes because the amount of change in length produced by the piezoelectric element is very small (about 10 micrometer).
Some other vibration control systems are disclosed in document 2 (Dai 32 Kai Uchukagakugijutsukoenkaikoenshu, pages 334 and 335), document 3 (Dai 31 Kai Uchukagakugijutsukoenkaikoenshu, pages 256 and 257), and document 4 (Dai 31 Kai Uchukagakugijutsukoenkaikoenshu, pages 398 and 399) and document 5 (Dai 31 Kai Uchukagakugijutsukoenkaikoenshu, pages 258 and 259).